The present invention relates to devices in which a shaft is rotatably mounted within a housing, by means of a set of bearings, and more particularly, to an improved bearing retention arrangement for use in such devices.
Although the present invention may be utilized with a number of different types of devices, it is especially advantageous when utilized in conjunction with a compound, change gear mechanical transmission, and will be described in connection therewith. The present invention is even more advantageous when utilized in such a transmission of the type including at least a pair of countershaft assemblies, and the invention will be described in connection therewith.
Typical compound change gear transmissions are illustrated and described in U.S. Pat. Nos. 4,290,515 and 4,736,643, both of which are assigned to the assignee of the present invention and incorporated herein by reference. Such transmissions include a main transmission section and an auxiliary transmission section, with the two sections being separated by a transverse wall portion, normally formed integrally with the transmission housing. The main transmission section includes a pair of countershafts, each of which is rotatably supported, within suitable bearings, by a forward wall of the transmission, and by the intermediate, transverse wall separating the transmission sections.
In many devices of the type described herein, the housing of the device is cast aluminum, or some aluminum alloy, while the outer race of the bearing set, which is disposed within an opening in the aluminum housing, is made from steel. The coefficient of thermal expansion of the aluminum differs substantially from that of the typical steel bearing race, and as a result, it has been known for the outer race of the bearing set to become loose within the housing bore at elevated temperatures, and merely rotate with the shaft and bearings.
In order to eliminate the possibility of the bearing set becoming loose within the housing bore, those skilled in the art have utilized bearing retainers, which are typically cylindrical, sleeve-like members which typically have a coefficient of thermal expansion closer to that of the bearing outer race. The bearing retainer receives the bearing outer race, and is received within the housing bore. One common arrangement has been to provide the bearing retainer with a radially-extending flange, which is then bolted to the aluminum housing, or attached thereto by some other suitable means, to ensure that there will be no rotation of either the bearing outer race or the retainer, relative to the housing bore.
The flange on the bearing retainer may also be useful in taking up some of the axial loading applied to the shaft being supported, such axial loading otherwise tending to move the bearing outer race axially relative to the housing bore. Unfortunately, there are a number of devices in which a shaft is rotatably mounted within a housing, by means of a bearing set, wherein the conventional, prior art bearing retainer sleeve either cannot be utilized, or if utilized, can only be installed in a manner which fails to take maximum advantage of the inherent benefits of the bearing retainer.